Fox Mulder & Dana Scully, 'The X-Files'

If there was ever a TV detective yin and yang, this pair is it. Mulder (David Duchovny) believed in conspiracies, cover-ups and extraterrestrials, and Scully (Gillian Anderson) was the pragmatic realist. They balanced each other out, but their oft-supressed sexual chemistry ensured that there were many more dimensions to their relationship.